Diabetes prevalence is associated with serum 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D in US middle-aged Caucasian men and women: a cross-sectional analysis within the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial

Hypovitaminosis D may be associated with diabetes, hypertension and CHD. However, because studies examining the associations of all three chronic conditions with circulating 25-hydroxyvitamin D (25(0H)D) and 1,25-dihydroxyvitamin D (1,25(0H)2D) are limited, we examined these associations in the US Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial (n 2465). Caucasian PLCO participants selected as controls in previous nested case-control studies of 25(0H)D and 1,25(0H)2D were included in this analysis. Diabetes, CHD and hypertension prevalence, risk factors for these conditions and intake of vitamin D and Ca were collected from a baseline questionnaire. Results indicated that serum levels of 25(0H)D were low (<50nmol/1) in 29% and very low ( < 37nmol/1) in 11% of subjects. The prevalence of diabetes, hypertension and CHD was 7, 30 and 10%, respectively. After adjustment for confounding by sex, geographical location, educational level, smoking history, BMI, physical activity, total dietary energy and vitamin D and Ca intake, only diabetes was significantly associated with lower 25(0H)D and 1,25(0H)2D levels. Caucasians who had 25(0H)D 2:80nmol/1 were half as likely to have diabetes (OR 0·5 (95% Cl 0·3, 0·9)) compared with those who had 25(0H)D /l. Those in the highest quartile of 1,25(0H)2D (/1) were less than half as likely to have diabetes (OR 0·3 (95% Cl 0·1, 0·7)) than those in the lowest quartile (< 72pmol/l). In conclusion, the independent associations of 25(0H)D and 1,25(0H)2D with diabetes prevalence in a large population are new findings, and thus warrant confirmation in larger, prospective studies.